Midair at FDK (Frederick, MD)

[Pedals2Paddles]

Still trying to find out details. I know a Cirrus popped their chute. I believe the other was a helicopter.

Edit/Update:
A cirrus (N122ES) and an R44 helicopter (N7518Q) collided in the pattern. The helicopter went down near some self storage units with all three killed. The cirrus popped the chute and is down in some fields and trees, not sure exactly. Serious injuries.

Audio from LiveATC is attached. Warning, it is bad.

 

[Jim Logajan]

Thanks.

I won't.

Seems reasonable. Only thing of learning value, if any, from the audio was that the tower warned the Cirrus pilot of 3 helicopters in the pattern. The Cirrus pilot appears to have acknowledged having 2 of the helicopters in sight. Doesn't mean the 1 unseen helicopter was the one they collided with, but the possibility comes to mind vs running into a helicopter you have acquired.

 

[Jim Logajan]

Look two posts up. I already pulled the audio and edited it down. It's bad. Just had to call all my friends and family to let them know it wasn't me. Sad day at the field.

What did you edit out?

 

[Jim Logajan]

Anyone know if TCAS or TIS would be standard or optional equipment in a 2006 SR22 like that which was involved in the midair?

 

[Jim Logajan]

Not quite. He should be looking and avoiding. I think it's safe to assume that, had he seen the helicopter in time to avoid it, he would have done so.

I count 6 people who didn't see anything in time who could have otherwise provided warning or taken action: the 3 in the helicopter, the 2 in the airplane, and 1 in the control tower. I count 0 who wanted it to happen.

 

[Jim Logajan]

What happened here was not a RoW issue though. RoW and steering rules do not exist until a risk of collision has been determined. Neither craft saw each other so no risk of collision could be determined.

This was not a failure in RoW, this was a failure in See and Avoid for which both parties are equally responsible for.

I agree - not sure why the "right of way" concept is being invoked at all. The concept of "right" pertains to decisions - and in the context of "right of way" it seems to pertain to decisions made when one is presented with conflicting traffic. Not seeing another aircraft at all pretty much negates the need for any decisions on whether one needs to alter course.

As to who failed at "see and avoid" could be neither - or both. Depends on what was physically or plausibly visible prior to the collision. Even with robot pilots with perfect vision in both the helicopter and the airplane, after you do the vector addition of velocities to find the family of relative closure vectors, you'll find collision vectors can come from all possible directions. But in virtually all aircraft you'll discover large of areas of the visibility sphere that surrounds the pilot are forever hidden from view.

 

[Jim Logajan]

No we don't. Once again, the helicopter the tower was talking to on the LiveATC recording was NOT the accident helicopter.

Turns out I still have a copy of the full audio (1930Z to 2000Z) on my computer from when I listened to it on LiveATC. Since your recollection conflicted with mine, I took the time to transcribe all the conversations that I could make out up until the collision (with the exception of the one clearance instruction and read back.) I inserted a [..?] at those points where they said something that I could not make out clearly. The occasional bits of unusual grammar are for the most part as best I could make out. I included the start and stop time of each transmission, measured from the hour. As you can see only 2 seconds elapsed between the end of the tower's last transmission to the Cirrus and the collision. So 8 seconds before the collision the tower had visually acquired the Cirrus and was watching it when the collision occurred (post-crash transcript would include tower saying she saw the collision.) What route and altitude did 18Q at? They seemed to be moving slow in the pattern given their departure time and final location.

2ES: The Cirrus that crashed. N122ES
18Q: The helicopter that crashed. N7518Q

• Twr 4:05 - 4:11: S122ES report 3 miles west for left downwind runway 30.
• Twr 4:15 - 4:20: 4PH is that you option in the grass at your own risk use caution you were stepped on.
• 4PH 4:20 - 4:23: Yes sorry about that 4PH option in the grass.
• 18Q 4:25 - 4:32: [..?] at advance would like to depart to for left closed traffic to the grass and we have the two helicopters in sight.
• Twr 4:34 - 4:37: 18Q you wanted to depart alpha you said?
• 18Q 4:33 - 4:39: That's affirmative and we have papa.
• Twr 4:40 - 4:51: 18Q ah departure from alpha at your own risk, correction, taxiway alpha cleared for takeoff, wind 330 at 13 gust 20 cleared for takeoff report turning left base.
• 18Q 4:51 - 4:54: Cleared for takeoff report left base 18Q.
• 144 4:55 - 4:58: [..?] 144 turning final for the grass.
• Twr 4:59 - 5:01: 144 for option at the grass at your own risk use caution.
• ??? 5:02 - 5:04: [..?] Option at the grass [..?]
• Twr 5:06 - 5:06: Roger
• Twr 5:12 - 5:20: 43T I don't know if I'll be able to complete this approach for you I have three helicopters in left traffic and a fixed wing inbound from the west.
• Twr 5:44 - 6:28: Citation 612JD your clearance is available. [Clearance instructions to Greensboro.]
• 2JD 6:31 - 6:48: Citation 612JD is cleared to Greensboro, [Clearance read back.]
• Twr 6:51 - 6:59: 4PH option at the grass use at your own risk use caution, and at the next go-around stay at a thousand feet I have traffic in the downwind.
• 4PH 7:00 - 7:03: Cleared for the option the grass stay at a thousand next go-around 4PH.
• Twr 7:03 - 7:10: 2ES report midfield left downwind for runway 30 have three helicopters below you in the ah traffic pattern.
• 2ES 7:11 - 7:15: I will report midfield downwind and I have two of them in sight [..?]
• Twr 7:16 - 7:22: Alright 2ES I have you in sight runway 30 maintain your altitude to until turning base, cleared to land.
• 7:24: [Open mike sounds of collision aftermath.]

 

[Jim Logajan]

Turns out I still have a copy of the full audio (1930Z to 2000Z) on my computer from when I listened to it on LiveATC.
[...]
2ES: The Cirrus that crashed. N122ES
18Q: The helicopter that crashed. N7518Q

• Twr 4:05 - 4:11: S122ES report 3 miles west for left downwind runway 30.
• Twr 4:15 - 4:20: 4PH is that you option in the grass at your own risk use caution you were stepped on.
• 4PH 4:20 - 4:23: Yes sorry about that 4PH option in the grass.
• 18Q 4:25 - 4:32: [..?] at advance would like to depart to for left closed traffic to the grass and we have the two helicopters in sight.
• Twr 4:34 - 4:37: 18Q you wanted to depart alpha you said?
• 18Q 4:33 - 4:39: That's affirmative and we have papa.
• Twr 4:40 - 4:51: 18Q ah departure from alpha at your own risk, correction, taxiway alpha cleared for takeoff, wind 330 at 13 gust 20 cleared for takeoff report turning left base.
• 18Q 4:51 - 4:54: Cleared for takeoff report left base 18Q.
• 144 4:55 - 4:58: [..?] 144 turning final for the grass.
• Twr 4:59 - 5:01: 144 for option at the grass at your own risk use caution.
• ??? 5:02 - 5:04: [..?] Option at the grass [..?]
• Twr 5:06 - 5:06: Roger
• Twr 5:12 - 5:20: 43T I don't know if I'll be able to complete this approach for you I have three helicopters in left traffic and a fixed wing inbound from the west.
• Twr 5:44 - 6:28: Citation 612JD your clearance is available. [Clearance instructions to Greensboro.]
• 2JD 6:31 - 6:48: Citation 612JD is cleared to Greensboro, [Clearance read back.]
• Twr 6:51 - 6:59: 4PH option at the grass use at your own risk use caution, and at the next go-around stay at a thousand feet I have traffic in the downwind.
• 4PH 7:00 - 7:03: Cleared for the option the grass stay at a thousand next go-around 4PH.
• Twr 7:03 - 7:10: 2ES report midfield left downwind for runway 30 have three helicopters below you in the ah traffic pattern.
• 2ES 7:11 - 7:15: I will report midfield downwind and I have two of them in sight [..?]
• Twr 7:16 - 7:22: Alright 2ES I have you in sight runway 30 maintain your altitude to until turning base, cleared to land.
• 7:24: [Open mike sounds of collision aftermath.]

Over on the purple board, user newlangsyne filled in and corrected some of the parts I didn't get (also here), so here's an updated transcript (updated portions underlined).

2ES: The Cirrus SR22 that crashed; N122ES.
18Q: The Robinson R44 that crashed; N7518Q.

• Twr 3:53 - 3:54: Cirrus 122ES, Frederick.
• 4PH 4:01 - 4:02: Tower, 4PH [unintelligible] left downwind for the grass.
• Twr 4:05 - 4:11: S122ES report 3 miles west for left downwind runway 30.
• Twr 4:15 - 4:20: 4PH is that you option in the grass at your own risk use caution you were stepped on.
• 4PH 4:20 - 4:23: Yes sorry about that 4PH option in the grass.
• 18Q 4:25 - 4:32: Tower, helicopter 7518Q at Advanced would like to depart to for left closed traffic to the grass and we have the two helicopters in sight.
• Twr 4:34 - 4:37: 18Q you wanted to depart alpha you said?
• 18Q 4:33 - 4:39: That's affirmative and we have papa.
• Twr 4:40 - 4:51: 18Q ah departure from alpha at your own risk, correction, taxiway alpha clear for takeoff, wind 330 at 13 gust 20 clear for takeoff report turning left base.
• 18Q 4:51 - 4:54: Clear for takeoff report left base 18Q.
• 42U 4:55 - 4:58: Tower, helicopter 42U turning final for the grass.
• Twr 4:59 - 5:01: 42U option at the grass at your own risk use caution.
• 42U 5:02 - 5:04: Option in the grass for simulated engine failure 42U.
• Twr 5:06 - 5:06: Roger.
• Twr 5:12 - 5:20: 43T I don't know if I'll be able to complete this approach for you I have three helicopters in left traffic and a fixed wing inbound from the west.
• Twr 5:44 - 6:28: Citation 612JD your clearance is available. [Clearance instructions to Greensboro.]
• 2JD 6:31 - 6:48: Citation 612JD is cleared to Greensboro, [Clearance read back.]
• Twr 6:51 - 6:59: 4PH option in the grass use at your own risk use caution, and on the next go-around stay at a thousand feet I have traffic in the downwind.
• 4PH 7:00 - 7:03: Cleared for the option the grass stay at a thousand next go-around 4PH.
• Twr 7:03 - 7:10: Cirrus 2ES report midfield left downwind for runway 30 I have three helicopters below you in the ah traffic pattern.
• 2ES 7:11 - 7:15: I will report midfield downwind and I've got two of them in sight 122ES.
• Twr 7:16 - 7:22: Alright 2ES I have you in sight runway 30 maintain your altitude to until turning base, cleared to land.
• --- 7:24 - 7:29: [Open mike sounds of collision aftermath.]
• 42U 7:31 - 7:33 Frederick Tower, 42U, airplane down and helicopter down.
• Twr 7:34 - 7:38 Yes, yes, I just saw it, 911's on the way.

 

[Jim Logajan]

That is what is known. If the helicopter was moving as slow as one witness reports the cirrus pilot just ran them down. If you fly into a hovering/slower moving helicopter at the same altitude it is your fault.

It sounds like the helicopter was hovering slowly or stationary in the downwind near pattern altitude while its pilot presumably listened to the tower direct an airplane toward his position and made no attempt to move forward or downward or give a radio alert of his blocking the path of the airplane.

But assuming for the moment that the airplane pilot is at fault, that issue of fault per se is of no value in mitigating future such accidents. Unless you think the airplane pilot deliberately collided with the helicopter, or his ego or thinking so skewed that he expected the helicopter to give way, the only issue left is to determine why the airplane pilot or his passenger was not able to see the helicopter.

One possibility is that over flat terrain, a helicopter just needs to below the head of the airplane pilot for it to appear among the ground clutter. One visual cue I can think of that would make it stand out is that it will grow more quickly in size than the more distant ground objects. Otherwise it would likely be difficult to see.

 

[Jim Logajan]

Look we all know pilots don't look outside for beans.

In this specific case the Cirrus pilot did look outside since he was told about 3 helicopters and said he spotted 2. It doesn't matter what you may claim about the general case - in this specific case the Cirrus pilot did look and knew what to look for and reported what he saw. Other than momentary setting of some controls and checking speed and altitude, a pilot's eyes are outside when approaching the landing pattern in VMC. It is an oddball claim to say otherwise since past research found even outside the pattern: "According to a U.S. study, private pilots on VFR flights spend about 50 per cent of their time in outside traffic scan (Suzler and Skelton 1976)."
Limitations of the See-and-Avoid Principle, Australian - Transport Safety Bureau
http://www.skybrary.aero/bookshelf/books/259.pdf

And in another study report:The see-and-avoid concept has physical and behavioral limitations such that pilots cannot reliably see and avoid conflicting aircraft. Pilots can find it physically impossible to see converging aircraft, especially when climbing or descending in an airport traffic pattern. Also, because human information processing is biased toward detection of contrast and sudden change, the small, motionless, camouflaged target projected by a rapidly converging aircraft is difficult to detect within the random and narrow window of opportunity to see and avoid it.
...These findings challenge the view that most midair collisions involve inadequate visual scanning (21,23).
...
Midair Collisions: Limitations of the See-and-Avoid Concept in Civil Aviation - C. Craig Morris
http://www.ingentaconnect.com/content/asma/asem/2005/00000076/00000004/art00007?crawler=true

Pilots need to be better at it, especially in the traffic pattern and certainly at a class d(o nothing) airport.

That's a reasonable proposal. However according to the reports I linked to, researchers since the 1970's have criticized see-and-avoid as fundamentally flawed when applied to vehicles traveling at high speeds. From the Australian publication: "See-and-avoid has been described as a maritime concept originally developed for slow moving ships which is now out of place in an era of high speed aviation (Marthinsen 1989)."
Part of its conclusion: "The see-and-avoid principle in the absence of traffic alerts is subject to serious limitations. It is likely that the historically small number of mid-air collisions has been in a large part due to low traffic density and chance as much as the successful operation of see-and-avoid.
... The most effective response to the many flaws of see-and-avoid is to minimise the reliance on see-and-avoid in Australian airspace."

Or we need to take your plan one step further, ADS-B and autopilots that can't be overriden above 200'. Program where you want to go, takeoff fly to 200' and let the computer sort traffic and details. You get the plane back at 200' on final. And of course kill all aviation that can't comply with that. Or keep on doing what we are doing and accept the occasional carnage.

Midair collisions are so rare that the 22nd Nall Report categorized them under "Unusual Accident Categories" and stated: "Fourteen fatal accidents and another 17 that were not fatal arose from circumstances too rare to support tabulation as separate categories for statistical analysis. In part because they were so unusual, however, many received extensive coverage in the general media."
Any future steps should consume resources proportionate to the risk; no more, no less. People often get their priorities wrong when evaluating risk when presented with accidents like this.

 

[Jim Logajan]

Will looking at a screen trying to resolve three helicopter targets below you really help? While looking outside, configuring for landing, and flying the plane. The sailplane guys have their own system, FLARM, and while they like it they do report target saturation. I believe there is a thermalling algorithm to quiet it down when going round and round with your friends in close proximity. Does ADS-B have conflict resolution? Are hobby pilots switched on enough to follow it in the traffic pattern?

I think one reason the FAA was requiring high position resolution was because it was needed for accurate relative position in close-quarters of a traffic pattern; something they concluded after testing with off-the-shelf non-WAAS GPS units. The other thing that ADS-B In units were expected or desired to do was to do some basic threat analysis and provide aural alerts on high-priority threats to lower the demands on the pilot, who was still expected to keep his or her eyes outside. The moving-maps on tablets with ADS-B In displays that do no threat analysis and no aural alerts are better than nothing, but are less than optimal or intended.

With regard to FLARM - I believe most, if not all, European glider contests now require contestant glider to be equipped with FLARM. Allegedly they went from having mid-air collisions on an almost yearly basis to now almost none: http://www.flarm.com/news/presscoverage/SSA_MainArticle_201405.pdf

 

[Jim Logajan]

*Disclaimer: Forget all of this rant, if ADS-B isn't so dependent upon GPS as represented here, and that in fact, it gets it's location information from some other (redundant) means.

The ADS-B specification does not require use of GPS, but the allowed position error and reliability of the position source pretty much rule out most current technologies other than WAAS GPS. Pragmatically speaking it is dependent on GPS and WAAS.

 

[Jim Logajan]

News here (WBOC) just reported that the Cirrus pilot told MSP that his traffic alert system didn't work as it should have. Wonder did the helo have transponder on? Wouldn't the traffic system need that?

Found a story here:
http://www.fredericknewspost.com/news/disasters_and_accidents/vehicular/pilot-alert-system-gave-no-warning-before-fatal-midair-collision/article_6fe3383b-4cd4-5eb5-b87c-69f503b57287.html?mode=jqm

 

[Jim Logajan]

From the story linked in post #558 Dunno if that is from pilot interview if so of course he is going to say that, if it is from the Cirrus box or radar the helicopter pilots screwed up.
The Cirrus collided with the helicopter, a Robinson R44, about 1,100 to 1,200 feet above ground at about 3:40 p.m., according to the National Transportation Safety Board's preliminary report.

Not sure where the reporter got the 1,100 to 1,200, but I am unable to find anything in the online preliminary reports that gives any clues on the altitude of the collision:

http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20141023X01333&key=2

http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20141023X01333&key=1

It is interesting to compare the two reports; I'd expect them to be identical except for the aircraft ID in the header. But there is a slight differences in the body of two paragraphs1) Witnesses on the ground observed the aircraft converge at the same altitude. One witness said the helicopter appeared to be in a stationary hover as the airplane approached it and the two subsequently collided. She said neither aircraft changed altitude as they approached each other.

A flight instructor for the operator in another company helicopter followed the accident helicopter in the traffic pattern for landing abeam runway 30. He said his helicopter had just completed the turn onto the crosswind leg of the traffic pattern, when the accident helicopter came into his view. At the same time, the airplane appeared in his field of view as it "flew through the rotor system" of the helicopter.
(2) Witnesses on the ground observed the aircraft converge at the same altitude. One witness who observed both aircraft converge indicated that neither aircraft changed altitude as they approached each other and the two subsequently collided.

A flight instructor for the operator in another company helicopter followed the accident helicopter in the traffic pattern for landing abeam runway 30. He said his helicopter had just completed the turn onto the crosswind leg of the traffic pattern, when the accident helicopter came into his view. At the same time, the airplane appeared in his field of view as it collided with the helicopter rotor system.